Steel for a knife

[Stubby]

It will take a good edge and as long as you only use it as a marking implement it will be fine, retired files used to be used as scrapers.

 

Heat treating can be used to alter the properties of steel, it changes the structure giving it different characteristics within the limits of its composition.

 

The working corner on a scraper is much wider than the angle on a knife so less likely to break . I have made scrapers from files to flatten a surface table . ( old school ) Also I understand heat treatment of steels having been a tool maker for 30+ years .

[mickdundee]

At the risk of experiencing the wrath of others I can't see why you would need to heat treat the file as it should take a good edge untreated. The marking knife I made from a file takes a good edge with no apparent down sides. Sure it's probably not the best steel in the world but it's a long way from being the worst

 

 

 

I googled making a knife from a file and found a step by step guide on the instructables website. The main reason given was to soften the file so it could be worked, then needed to be rehardened to take a good edge

 

 

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[agrimog]

if you have any friends who are into knifemaking, your old cutting chains make excellent blades and the damascus pattern is amazing, but you need a knowledge of firewelding and forging

[openspaceman]

if you have any friends who are into knifemaking, your old cutting chains make excellent blades and the damascus pattern is amazing, but you need a knowledge of firewelding and forging

 

 

I've seen this on the internet but wondered what happens to the chrome plating, does it get lost or become part of the alloy? The thing is I have never got a good edge on stainless steel and sort of thought this may be due to the presence of chromium.

 

Late to the fray, because I've been making a fool of myself in the Ogwen valley, I did make some gouges for spoon carving from old flat files, heat the lot up to dull red and allow to cool slowly to make the steel less brittle, form the cutting "spoon" at red heat and then quench the cutting edge in a potato which hardens the tip and then let the residual heat temper the cutting edge to straw colour before quenching in water. Worked for me.

 

Originally I was told that files were pre hardened and then the teeth were etched with acid, is this still the case.

 

I often wonder if there is a service that can analyse the content of a steel alloy, other than the spark test Bob mentioned, to see what other elements are used to change characteristics and whether they are machineable or weldable.

 

As we all know chainsaw files are very brittle but when I lost one of the S hooks on a hammock I heated one up and shaped it with the Oxy-acetylene and made a replacement which held me up with no problems, the brittleness comes from the rapid cooling forming smaller crystals of iron with the carbon interspersed in the matrix which holds the iron in place and stops it deforming as it can in the larger crystals formed during slower cooling.

[treequip]

I've seen this on the internet but wondered what happens to the chrome plating, does it get lost or become part of the alloy? The thing is I have never got a good edge on stainless steel and sort of thought this may be due to the presence of chromium.

 

Late to the fray, because I've been making a fool of myself in the Ogwen valley, I did make some gouges for spoon carving from old flat files, heat the lot up to dull red and allow to cool slowly to make the steel less brittle, form the cutting "spoon" at red heat and then quench the cutting edge in a potato which hardens the tip and then let the residual heat temper the cutting edge to straw colour before quenching in water. Worked for me.

 

Originally I was told that files were pre hardened and then the teeth were etched with acid, is this still the case.

 

I often wonder if there is a service that can analyse the content of a steel alloy, other than the spark test Bob mentioned, to see what other elements are used to change characteristics and whether they are machineable or weldable.

 

As we all know chainsaw files are very brittle but when I lost one of the S hooks on a hammock I heated one up and shaped it with the Oxy-acetylene and made a replacement which held me up with no problems, the brittleness comes from the rapid cooling forming smaller crystals of iron with the carbon interspersed in the matrix which holds the iron in place and stops it deforming as it can in the larger crystals formed during slower cooling.

 

 

The chrome remains "as is" and is incorporated into the remainder of what is fairly low carbon steel. It isn't strictly correct to describe it was an alloy, it would be best described as mainly steel of a slightly better than average carbon content with inclusions of other materials.

 

For it to become a true alloy you would need a lot more heat and probably some flux to bind the slag which would give you some sort of ferrochrome or possibly stainless, depending on the ratio of materials.

 

Forging saw chain gives a good decorative effect that some will call damask but metallurgicaly speaking its no where near. Its also a PITA if the edge has a chunk of chrome in. Better as a "wall hanger" than a working knife.

 

File teeth are hot rolled to shape the then acid etched to give them the edge, the etching is a cold process and if they aren't too badly damaged files can be re etched to bring the edge back but AFAIK this hasn't been common practice since we entered the disposable era, etching is pretty much the only way to edge a file.

 

As far as analysing alloy content with any accuracy goes, expensive terms like gas chromatograph spring to mind, probably not cost effective unless you definitely had to know, you can pretty much tell what you need to know when you get it on the anvil

[bob]

I have a few old chipper blades of varying sizes (bigger mainly)

Presume they would make nice knives though a lot of work to get to right width I would imagine.

Shame as seems a shame to scrap them.

[openspaceman]

I have a few old chipper blades of varying sizes (bigger mainly)

Presume they would make nice knives though a lot of work to get to right width I would imagine.

Shame as seems a shame to scrap them.

 

Yes, we dispose of heizohack blades after one use and they seem to take a bit of abuse so I wonder about using them for something else.